NXP Semiconductors
FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
Table 168.ꢀSystem background debug force reset register (SBDFR)
Bit
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
BDFR[1]
0
W
Reset
0
0
0
0
0
0
0
= Reserved
[1] BDFR is writable only through serial BACKGROUND mode debug commands, not from user programs.
Table 169.ꢀSBDFR register field description
Field
Description
Background Debug Force Reset — A serial ACTIVE BACKGROUND mode command such as WRITE_
BYTE allows an external debug host to force a target system reset. Writing 1 to this bit forces an MCU
reset. This bit cannot be written from a user program.
0
BDFR
18 Battery charge consumption modeling
The supply current consumed by the FXTH87E can be estimated using the following
basic model.
18.1 Standby current
The overall charge consumed by the standby features is:
(13)
where:
• QSTDBY = Standby charge over lifetime, tTOT, in mA-hr
• tTOT = Total lifetime in hours
• ISTDBY = General standby current in μA
• ILF = LFR detector (if used) current in μA
18.2 Measurement events
The overall charge consumed by the measurements is:
(14)
where:
• QMEAS = Total measurement charge over lifetime in mA-sec
• QPRESS = Measurement charge per pressure measurement in μA-sec
• QTEMP = Measurement charge per temperature measurement in μA-sec
• QVOLT = Measurement charge per voltage measurement in μA-sec
• nPRESS = Total number of pressure measurements over lifetime
• nTEMP = Total number of temperature measurements over lifetime
FXTH87ERM
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Reference manual
Rev. 5.0 — 4 February 2019
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